According to Anthony S. Fauci, M.D., Director at the National Institute of Allergy and Infectious Diseases (NIAID), finding a safe and effective vaccine to prevent infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an urgent public health priority.

Developing a vaccine to protect against SARS-CoV-2 infection is critical because of the large number of people infected, the ability of the virus to spread from person to person, and the spread of the virus across so many geographic areas.

Despite global efforts, however, the World Health Organization estimates 18 months before a vaccine against the coronavirus is publicly available. At present, about 80 companies and academic institutions are racing to find a vaccine, and of those, five are now testing their vaccine candidates in people. The first of these to enter human trials did so in March.

On March 16, investigators at Kaiser Permanente Washington Health Research Institute (KPWHRI) in Seattle and Emory University in Atlanta, initiated a clinical trial of an investigational vaccine, called mRNA-1273, which was developed using messenger RNA (mRNA) and has shown promise in animal models. The investigational vaccine directs the body’s cells to express a virus protein that hopefully will elicit a robust immune response.

In the first phase of this open-label trial, researchers are testing the safety of various doses and whether these doses produce an immune response. The trial was originally designed to enroll 45 healthy participants ages 18 to 55 years. Once 45 participants were enrolled, the investigators expanded the trial to enroll an additional 60 participants: 30 adults ages 56 to 70 years and 30 adults ages 71 years and older in an effort to help investigators understand the safety and immune response among older people who face a higher risk of complications from COVID-19 than younger people. Safety reviews have not revealed any significant issues among younger participants.

Participants (15 in each experimental arm) will receive two doses of the vaccine via intramuscular injection in the deltoid muscle approximately 28 days apart. Each participant will be assigned to receive a 25 microgram (mcg), 100 mcg, or 250 mcg dose at both vaccinations.

The first four participants will receive one injection with the low dose, and the next four participants will receive the 100-mcg dose. Investigators will review safety data before vaccinating the remaining participants in the 25 and 100 mcg dose groups and before participants receive their second vaccinations.

Experimental: Arm 1
25 mcg of mRNA-1273 administered through 0.5 mL intramuscular injection in the deltoid muscle on Days 1 and 29, n=15 (4 sentinel, 11 non-sentinel).

Experimental: Arm 2
100 mcg of mRNA-1273 administered through 0.5 mL intramuscular injection in the deltoid muscle on Days 1 and 29, n=15 (4 sentinel, 11 non-sentinel).

Experimental: Arm 3
250 mcg of mRNA-1273 administered through 0.5 mL intramuscular injection in the deltoid muscle on Days 1 and 29, n=15 (4 sentinel, 11 non-sentinel).

Clinicians will monitor participants for common vaccination symptoms, such as soreness at the injection site, fever, and any other medical issues. A protocol team will meet regularly to review safety data, and a safety monitoring committee will also periodically review trial data and advise NIAID. Participants will provide blood samples at specified time points so that investigators can detect and measure the immune response.